<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        *{
            margin: 0;
            padding: 0;
             /*input a button img 浏览器轮廓不统一*/
            outline: 0; 
        }
        a {
            text-decoration: none;
            color:inherit;
        }
        .pj_tabbar {
            display:flex;
        }
        .pj_tababbar__item {
            flex:1;
            height:50px;
            border-bottom: 1px solid #ddd;
        }
        .pj_tababbar__item a {
            display: block;
            line-height: 50px;
            text-align: center;
        }
        .pj_tababbar__item a:first-child {
            border-right:1px solid #ddd;
        }
        .pj_tababbar__item_on {
            background-color: pink;
            color:white;
        }
    </style>
</head>
<body>
    <div class="pj_tabbar">
        <div class="pj_tababbar__item pj_tababbar__item_on">
            <a href="#" data-type="basic">
                basic
            </a>
        </div>
        <div class="pj_tababbar__item">
            <a href="#" data-type="super">
                super
            </a>
        </div>    
    </div>
    <div id="list">

    </div>
    <script>
        const list = document.getElementById('list');
        const links = document.querySelectorAll('.pj_tababbar__item a');

        // const tabTypes = {
        //     basic:Symbol(),  /* es6 里新的数据结构，独一无二*/
        //     super:Symbol()
        // }
        // java 等大型语言，tab 切换时， 为了可读性 对象常量
        // 所有tab类型的管理 统一的地方
            const tabTypes = {
                basic:'basic',
                super:'super'
            }

        // 监听元素不能集合一起监听，只能一个个监听
        links.forEach(link => {
            link.addEventListener('click',function(event) {
                // a 带来交互感觉
                // console.log('11');
                event.preventDefault();
                const type = event.target.dataset.type;
                const parent = this.parentNode;
                if(!parent.classList.contains('pj_tababbar__item_on')) {
                    document.querySelector('.pj_tababbar__item_on')
                        .classList.remove('pj_tababbar__item_on');
                    parent.classList.add('pj_tababbar__item_on');
                }
                if(type == tabTypes.basic){
                    list.innerText = 'basic';
                }
                if(type == tabTypes.super){
                    list.innerText = 'super';
                }
            });
        })
    </script>
</body>
</html>